Re: [RFC][PATCH 4/4] drm: i915: Atomic pageflip WIP

On Wed, 12 Sep 2012 18:47:07 +0300, ville.syrjala@linux.intel.com wrote:

+static void intel_flip_finish(struct drm_flip *flip) +{

• struct intel_flip *intel_flip =

• container_of(flip, struct intel_flip, base);
  

• struct drm_device *dev = intel_flip->crtc->dev;
• if (intel_flip->old_bo) {

• mutex_lock(&dev->struct_mutex);
  

• intel_finish_fb(intel_flip->old_bo);
  

So if I understand correctly, this code is called after the flip is already complete?

The intel_finish_fb() exists to flush pending batches and flips on the current fb, prior to changing the scanout registers. (There is a hardware dependency such that the GPU may be executing a command that required the current modesetting.) In the case of flip completion, all of those dependencies have already been retired and so the finish should be a no-op. And so it should no be required, nor the changes to intel_finish_fb (which should have included a change in the name to indicate that is now taking the fb_obj).

• intel_unpin_fb_obj(intel_flip->old_bo);
  

• mutex_unlock(&dev->struct_mutex);
  

• }

+}

-Chris